The resin dispensing technology is based on dispensing two or more liquid resin components, with a manually operated applicator which keeps the reactive components separate until they reach a mixing area. As is known, once the two or more components are combined in the mixing area, the components react with each other to produce a settable material such as a quickly curing urethane foam. Prior devices include numerous configurations for activation of the trigger, various valve concepts and different discharge characteristics. There are numerous variations of the types of foam dispensing applicators, however all such variations have drawbacks to a greater or lesser degree that have not been fully resolved.
One such problem is that the one of the reactive components may flow rearward into the flow passage of another component in the dispenser, where the passages may become clogged by the reacted component materials. This situation is commonly called “cross-over”, and can cause clogging and failure of the dispensing applicator. One occurrence that can cause the potential for crossover is that of a blockage in the mixing area in the nozzle. When the nozzle of this type of applicator becomes blocked, there is a potential that one component may flow into the mixing area and have no where to flow except rearward into the flow path of another component. This undesirable situation may render the applicator useless, and result in a loss of time and resin component material.